If $x \veebar y = x-7y$ and $x \diamond y = 3x^{2}+y^{2}$, find $-2 \diamond (-3 \veebar -1)$.
First, find $-3 \veebar -1$ $ -3 \veebar -1 = -3-(7)(-1)$ $ \hphantom{-3 \veebar -1} = 4$ Now, find $-2 \diamond 4$ $ -2 \diamond 4 = 3(-2)^{2}+4^{2}$ $ \hphantom{-2 \diamond 4} = 28$.